The present invention relates to a network system comprised of a plurality of electronic musical equipments, which are set up on a communication network, and which are interconnected to each other by logical paths.
Generally, a plurality of electronic musical instruments can be mutually connected to construct a network system by means of Musical Instrument Digital Interface (MIDI). The MIDI is a standard interface accepted worldwide. The electronic musical instrument can transmit a musical message containing performance information from an internal MIDI terminal according to the MIDI standard. In one application of the MIDI, a single player can concurrently operate a multiple of electronic musical instruments on a stage or else to perform a concert.
However, the MIDI is basically a serial and unidirectional interface. Therefore, a plurality of electronic musical instruments are connected in series by the MIDIs. One instrument only transmits performance information including note-on data and velocity data to another instrument in one way by a serial data format. In order to remove such a drawback, the inventors have proposed a new network system as disclosed in the U.S. patent application Ser. No. 08/388,982 filed Feb. 15, 1995. This new network system is constructed to form a plurality of logical paths in a common communication line to enable bidirectional transfer of musical messages among multiple of electronic musical equipments.
In the proposed network system, the multiple of the electronic musical equipments are distributed throughout a communication network composed of the logical paths. One equipment transmits performance information such as control messages in a sequence of data packets to the communication network. Occasionally, a control message goes astray so that a logical chain of sequential control messages is cut. In such a case, another equipment receives a logically inconsistent control message subsequent to a lost control message. The receipt of the inconsistent or confusing control message may disturb normal operation of the receiving equipment. For example, if a preceding key-on message is lost, the receiving equipment falls into disorder when receiving a succeeding key-off message because the key-off message logically must accompany the key-on message which is actually lost. Further, in case that the logical paths are incorrectly constructed in the communication network, an electronic musical equipment may receive a wrong control message to thereby fall into disorder. Moreover, in case that the transmitting equipment successively transmits control messages at a fast speed over a normal operation speed of the receiving equipment, the operation of the receiving equipment may be seriously disturbed.